Mac: Make TransportDIB::Create() work.

app/surface/transport_dib_mac.cc

Index: app/surface/transport_dib_mac.cc
diff --git a/app/surface/transport_dib_mac.cc b/app/surface/transport_dib_mac.cc
index f17835ff2fbc6e203cdf6fd7c8b979a74a0f2549..97d18d762d109afa9c9a8dea346634e28c48b544 100644
--- a/app/surface/transport_dib_mac.cc
+++ b/app/surface/transport_dib_mac.cc
@@ -34,6 +34,11 @@ TransportDIB* TransportDIB::Create(size_t size, uint32 sequence_num) {
     return NULL;
   }
 
+  if (!dib->shared_memory_.Map(size)) {
+    delete dib;
+    return NULL;
+  }
+
   dib->size_ = size;
   return dib;
 }